I was talking to Gametap tech support today to try to fix a movie issue I'm having (movies won't play at all) and I asked the support rep about upcoming systems. Here's the list that he confirmed they were "in talks with".
Apple II
Commodore 64
Playstation 1
Sega CD
He also said that this weekend, they were planning to get the game count up to 300. They currently have over a thousand games available, but it takes time to test and add them all.
Now, he's not an official PR rep, so take those systems with a grain of salt. He specifically mentioned about 175 different C64 games being looked at, so I'd say that's pretty definite.
